Early central nervous system complications after allogeneic hematopoietic stem cell transplantation in children

BACKGROUND: Central nervous system (CNS) complications after allogeneic hematopoietic stem cell transplantation (HSCT) have not been well characterized in the pediatric population. METHODS: We retrospectively analyzed data of 202 consecutive children who underwent allogeneic HSCT (60 from matched related donors, 9 from mismatched related donors, and 133 from unrelated donors) at Asan Medical Center between 1998 and 2009. RESULTS: Twenty-seven children (13.5%) developed CNS complications within 6 months after HSCT. Calcineurin inhibitor (CNI)-associated neurotoxicity was the most common CNS complication (n=16), followed by CNS infection (n=2), cerebrovascular events (n=2), thrombotic microangiopathy-associated events (n=2), metabolic encephalopathy (n=2), irradiation/chemotherapy injury (n=1), and encephalopathy/myelopathy of unknown causes (n=2). Univariate analysis showed that a transplant from an alternative donor and the occurrence of acute graft-versus-host disease (GVHD) (>grade 2) were associated with a significantly increased risk of CNS complications. In the multivariate analysis, acute GVHD >grade 2 was identified as an independent risk factor for early CNS complications. The 5-year overall survival rate was significantly lower in patients with CNS complications (52.1% vs. 64.9%, P=0.014), whereas CNI-associated neurotoxicity did not affect the survival outcome. CONCLUSION: CNS complications are frequent among children undergoing HSCT, contributing to early death after transplant. More attention should be paid to the development of CNS complications for recipients of alternative donor transplants and patients with severe acute GVHD who are at increased risk for CNS complications.